I actually wrote an article on this topic and about how to keep things flowing in a natural way, I hope you find it useful :) Idan Altman | Indie Music Producer
I definitely don't think that your expectations are too high. For me a large part of mastering is making sure that the client is improving their mixing skills even if its means that on the long run they might not require my services at some point. There is nothing more satisfying than know that...